McGILL BIRD OBSERVATORY

PHOTO LIBRARY

Slate-colored Junco / Junco ardoisé (Junco hyemalis)


 Introductory notes:
While ageing is often quite simple for Slate-colored Junco due to distinct molt limits on many HY/SY birds, these can sometimes be subtle, so more caution is advised for those that appear to be AHY/ASY.  Also, determination of sex can be trickier as there is a gradient of plumage colouration, and as such HY/SY males and AHY/ASY females may require care to differentiate.


QUICK TIPS:
1) Look at the back and head - AHY/ASY males are dark gray with little or no brown, HY/SY males and AHY/ASY females are medium gray with brown especially on the back, and HY/SY females are brownish-gray and paler than other ages/sexes

2) Examine the greater coverts - HY/SY birds often have a conspicuous molt limit among the greater coverts with retained brown outer coverts contrasting with replaced gray inner coverts, while AHY/ASY birds have uniform greater coverts

3) Look at the primary coverts - on HY/SY birds they are brownish-gray and contrasting with the gray replaced inner greater coverts, while on AHY/ASY birds they are uniform in colour and wear with the greater coverts

4) Check the tail - on HY/SY birds the outer rectrices are narrow and tapered, while on AHY/ASY birds they are broad and rounded; note that the amount of white does not appear to reliably correspond to age or sex

5) In fall and winter, look at the iris under good light - it is grayish-brown on HY/SY birds, and reddish-brown on AHY/ASY birds

Note:  there are several subspecies of Dark-eyed Junco in North America; the descriptions provided are for the eastern race, Slate-coloured Junco, but comments regarding moult limits and feather shape/condition are likely broadly applicable to other races too.

Species account updated January 2011

  Ageing and sexing guidelines:

January - July:

ASY - M
Dark gray above, with little brown on the back; wing uniformly dark gray; rectrices broad and rounded.
     
ASY - F
Gray above, with moderate to extensive brown on the back.  Wing entirely gray; rectrices broad and rounded.
SY - M
Gray to dark gray above, with moderate to extensive brown on the back.  Primary coverts brownish; molt limit among greater coverts or between the greater and primary coverts; rectrices narrow and tapered.
SY - F
Gray above, with moderate to extensive brown on the back.  Primary coverts brownish; molt limit among greater coverts or between the greater and primary coverts; rectrices narrow and tapered.

-

July - December:

AHY - M
Dark gray above, with little brown on the back; wing uniformly dark gray; rectrices broad and rounded.
AHY - F
Gray above, with moderate to extensive brown on the back.  Wing entirely gray; rectrices broad and rounded.
HY - M
Gray to dark gray above, with moderate to extensive brown on the back.  Primary coverts brownish; molt limit among greater coverts or between the greater and primary coverts; rectrices narrow and tapered.
HY - F
Gray above, with moderate to extensive brown on the back.  Primary coverts brownish; molt limit among greater coverts or between the greater and primary coverts; rectrices narrow and tapered.

Ageing and sexing details:

JAN - JUL:  after-second-year male

ASY males are uniformly dark gray above, with few if any brown body feathers.
 


The wing of ASY male juncos is uniformly dark gray, with no contrast in colour or condition between any feather tracts.
 


ASY males have broad and rounded tails.  The amount of white on the outer three rectrices tends to be most extensive on ASY males, but there is considerable variation among and between races, and this feature cannot be used alone to age or sex individuals.
 

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JAN - JUL:  after-second-year female

There is some overlap between SY males and ASY females in overall appearance, but ASY females tend to be somewhat paler gray, and with more brown on the back.  Note that appearance may vary among individuals and can also be affected by lighting.  Age can usually be easily determined by looking at the wing and/or tail, and sex can be determined more reliably once age is known.


A fairly typical ASY female, with moderately dark gray on the head and some brown on the back.
Photo by Marcel Gahbauer, McGill Bird Obseravtory (QC), April 2006


A somewhat darker individual on the head, with less brown on the back, but some on the
breast (and also a short wing chord, as measured while in the hand).

Photo by Marie-Anne Hudson, McGill Bird Observatory (QC), April 2008


ASY juncos have a uniformly gray wing, with no contrast in colour or condition between feather tracts.


Photo by Marie-Anne Hudson, McGill Bird Observatory (QC), April 2008
 


Rectrices are broad and rounded, usually showing relatively little wear even by spring. 


Photo by Marcel Gahbauer, McGill Bird Observatory (QC), April 2006

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JAN - JUL:  second-year male

There is some overlap between SY males and ASY females in overall appearance, but SY males tend to be somewhat darker gray, and with less brown on the back.  Age can usually be easily determined by looking at the wing and/or tail, and should be done before considering sex. 


A typical SY male Slate-colored Junco; note that in some cases like this one, the molt limit
between the brownish juvenile alula and primary coverts vs. the grayish formative greater
and median coverts.

Photo by Marcel Gahbauer, McGill Bird Observatory (QC), January 2006


SY Slate-colored Juncos typically have a rather obvious molt limit within the greater coverts or between the greater coverts and primary coverts.


In this example, the molt limit is in the middle of the greater coverts, with the outer greater coverts
and primary coverts distinctly brownish, contrasting with the replaced inner greater coverts.

Photo by Marcel Gahbauer, McGill Bird Observatory (QC), January 2006


Although the wing is the most reliable for ageing juncos, SY birds typically also have somewhat more narrow and tapered outer rectrices. The extent of white on the outer rectrices appears to vary geographically as well as by age and sex, and is therefore of limited use for ageing or sexing.


Photo by Marcel Gahbauer, McGill Bird Observatory (QC), January 2006

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JAN - JUL:  second-year female

SY females are usually distinctly paler than any other juncos.  They are usually medium gray on the upper breast and back, mixed with some pale brown, sometimes leading to a bit of a pinkish tone.


Photo by Marcel Gahbauer, McGill Bird Observatory (QC), April 2006


SY juncos typically have a rather obvious molt limit among the greater coverts or between the greater coverts and primary coverts.


In this example, the outer two brownish greater coverts are retained juvenile feathers,
contrasting with the replaced formative inner greater coverts.

Photo by Marcel Gahbauer, McGill Bird Observatory (QC), April 2006


Although the wing is the most reliable feature for ageing juncos, the outer rectrices of SY individuals are usually somewhat more narrow and tapered than on ASY birds.  SY females typically have the least amount of white on the outermost three rectrices, but this is quite variable and not a reliable feature for ageing and sexing.


Photo by Marcel Gahbauer, McGill Bird Observatory (QC), April 2006

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JUL - DEC:  after-hatch-year male

ASY males are uniformly dark gray above, usually with only a bit of brown on the back.


A typical AHY male, with a dark face and only a hint of brown on the back.
Photo by Marcel Gahbauer, McGill Bird Observatory (QC), October 2009


Another typical AHY male, illustrating that due to feather edging, the wings and back
may appear contrastingly pale, but note the head is again uniformly dark.

Photo by Marcel Gahbauer, McGill Bird Observatory (QC), October 2010


The wing of AHY males is uniformly gray, with no contrast in colour or condition between any feather tracts.


A typical AHY male wing, dark gray throughout and with broad silvery edging on the
greater coverts and tertials.

Photo by Marcel Gahbauer, McGill Bird Observatory (QC), October 2009


AHY males have broad and rounded tails.  The amount of white on the outer three rectrices tends to be most extensive on AHY males, but there is considerable variation among and between races, and this feature should not be considered reliable for ageing or sexing individuals.


A typical AHY male tail, showing broad and rounded rectrices, and almost no dark patches
on the outermost three feathers.

Photo by Marcel Gahbauer, McGill Bird Observatory (QC), October 2005


Another example showing similar feather shape, but with a bit more dark on r4.
Photo by Marcel Gahbauer, McGill Bird Observatory (QC), October 2009


Again, similar rectric shape, but even more extensive dark patches on r4.
Photo by Marcel Gahbauer, McGill Bird Observatory (QC), October 2010

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JUL - DEC:  after-hatch-year female

There is some overlap between HY males and AHY females in overall appearance, but AHY females tend to be somewhat paler gray, and with more brown on the back and upper breast.  It is usually better to first determine age by looking at the wing and/or tail, then consider sex.


A typical AHY female, medium gray in colour with a bit of a darker face and a distinct brown
patch on the back. Note that although the primary coverts and greater coverts contrast in
colour, this is due to the brown edging on the greater coverts, but the primary coverts are
in fact dark and gray-edged, suggesting they are basic rather than juvenile feathers.

Photo by Marcel Gahbauer, McGill Bird Observatory (QC), October 2010


AHY females have uniformly gray primary and greater coverts, though there may be some brownish edging on inner greater coverts.


A typical AHY female wing, relatively uniformly gray, but a bit paler than that of a typical
AHY male.  Note that some greater coverts and tertials may have brownish edging.

Photo by Marcel Gahbauer, McGill Bird Observatory (QC), October 2010


Another example, somewhat duller overall, but again uniform in tone across the wing.
Photo by Marcel Gahbauer, McGill Bird Observatory (QC), October 2010


AHY juncos have broad and rounded tails.  The amount of white averages greater on AHY birds than on HY individuals, but not reliably so.


A typical AHY female wing, with broad and rounded rectrices, and a moderate amount of
dark on r4.

Photo by Marcel Gahbauer, McGill Bird Observatory (QC), October 2010


An AHY female with an unusually limited amount of white on r4.
Photo by Marcel Gahbauer, McGill Bird Observatory (QC), October 2010


An unusual case with white extending as far as r3.
Photo by Marcel Gahbauer, McGill Bird Observatory (QC), October 2005

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JUL - DEC:  hatch-year male

There is some overlap between HY males and AHY females in overall appearance, but HY males tend to be somewhat darker gray, especially in the face, and with less brown on the back and upper breast.  Age can usually be easily determined by looking at the wing and/or tail.


A typical HY male, darker on the head and upper breast than an average AHY female,
but also with a fair amount of brown on the back.

Photo by Marcel Gahbauer, McGill Bird Observatory (QC), October 2005


An example of how a HY male may appear somewhat paler in bright sunlight, highlighting
the care required with regarding subjective assessment of plumage.

Photo by Marcel Gahbauer, McGill Bird Observatory (QC), October 2010


A typical gray/brown pattern for a HY male, but with distinct white tips to the median
and greater coverts.

Photo by Marcel Gahbauer, McGill Bird Observatory (QC), October 2009


An example illustrating that sometimes the molt limits on the wing are prominently visible
even on perched birds, in this case the brown-edged juvenile outer greater coverts
contrasting witht he longer, darker, gray-edged inner greater coverts.

Photo by Marcel Gahbauer, McGill Bird Observatory (QC), November 2009


HY juncos can usually be aged easily by spotting distinct molt limits either among the greater coverts or between the greater coverts and primary coverts.  The primary coverts are usually brownish or brownish-gray, with minimal edging; retained juvenile greater coverts are also brownish and often have distinct pale tips.


A particularly distinct HY wing, with a sharp molt limit between the grayish replaced inner
greater coverts and the brown, white-tipped juvenile outer greater coverts.  More generally,
the gray median coverts and inner greater coverts contrast with the generally brownish
tone of the rest of the wing.

Photo by Marcel Gahbauer, McGill Bird Observatory (QC), November 2009


Fairly often, HY juncos have replaced all their greater coverts.  Although the molt limit isn't
quite as obvious as in the first example, there is nonetheless a distinct contrast between
the gray greater coverts and the block of more brownish retained feathers including
the primary coverts, primaries, and secondaries.

Photo by Marcel Gahbauer, McGill Bird Observatory (QC), October 2009


Although the wing provides the easiest and most reliable clues for ageing, the tail on HY juncos is usually also narrow and tapered, in contrast to the broader and more rounded shape typical of AHY juncos.  HY males typically have an intermediate amount of white on the outer rectrices, usually including at least some white on r4, but this is highly variable and not reliable for ageing and sexing.


A typical HY male tail, showing relatively narrow and tapered rectrices, already with a bit
of wear at the tips, and a moderate amount of white on r4.

Photo by Marcel Gahbauer, McGill Bird Observatory (QC), October 2009


A much fresher-loooking tail except for the tip of r3 on the right side, but note that again
the outer rectrices are quite narrow. In this case there is only a trace of white along
the shaft of r4, and even r5 is not entirely white.

Photo by Marcel Gahbauer, McGill Bird Observatory (QC), October 2005


Another example highlighting the typical shape of the outer rectrices, and again a moderate
amount of white on r4, but in this case also a dark outer edge to r5.

Photo by James Junda, McGill Bird Observatory (QC), September 2008

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JUL - DEC:  hatch-year female

Most HY females are distinctly paler than all other age/sex combinations in fall.  They are typically more brown than gray on the back, with a pale upper breast that is a mixture of light gray and brown and may even appear pinkish;  colouration also varies by subspecies as in other age/sex combinations.


A typical HY female, pale on the upper breast and head, and with a bit of a pinkish-brown tone.
Photo by Marcel Gahbauer, McGill Bird Observatory (QC), October 2005


This individual is more grayish, but still distinctly pale.  Note that the molt limit among the
greater coverts is visible even from this angle.

Photo by Marie-Anne Hudson, McGill Bird Observatory (QC), October 2007


A particularly brownish/pinkish example, with the breast almost suggestive of the
cismontanus subspecies, but difficult to be certain of since HY females of the eastern
subspecies
hyemalis can also have a pinkish tone sometimes.

Photo by Marie-Anne Hudson, McGill Bird Observatory (QC), October 2007


HY juncos can easily be aged by the presence of usually distinct molt limits within the greater coverts or between the greater coverts and primary coverts.


A typical HY female wing, largely brownish, with contrasting pale gray in the median and
greater coverts. Note the distinct molt limit between the replaced gray formative inner
greater coverts and the retained outermost two brownish ones. Also, the primary coverts
are distinctly brownish and lacking edging.

Photo by Marie-Anne Hudson, McGill Bird Observatory (QC), October 2007


Although the wing is best for ageing juncos, the tail is usually reliable too, with HY individuals having outer rectrices that are relatively narrow and tapered.  Females tend to average somewhat browner than males, and with a lesser amount of white on r4 and r5, but there is too much overlap for this to be reliable for sexing.


A fairly typical HY female tail, with narrow and tapered outer rectrices, and a general
brownish (rather than grayish) tone to the central rectrices.

Photo by Marie-Anne Hudson, McGill Bird Observatory (QC), October 2007

RETURN TO AGE/SEX OVERVIEW

 

2002- The Migration Research Foundation Inc.